JP2003324438A - Ethernet(r) communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication device having a redundant configuration in which a switching time is shortened without complicated protocol processing. <P>SOLUTION: When a fault on a corresponding link is detected, transmitting- receiving means 10 and 30 notify a link abnormality deciding means 51 of fault information. The link abnormality deciding means 51 decides whether a status of each link is normal or abnormal from the fault information. A switching control means 52 selects a link to acquire received data by using the decided result of the link abnormality deciding means 51. When the corresponding link is selected as the link to acquire the received data by the switching control means 52, the transmitting-receiving means 10 and 30 extract data received from the link as received data. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Ethernet communication device, and more particularly to an Ethernet communication device usable for a leased line.

[0002]

2. Description of the Related Art Conventionally, Ethernet has been used as a LAN interface. However, with the recent increase in data communication, a communication mode using Ethernet as a dedicated line has been required. Although the leased line is required to have high reliability of the transmission line, the reliability is also required for the communication device using the Ethernet interface.

Therefore, the redundant configuration means for the Ethernet interface is established in IEEE802.3 and the like. According to these, the redundant configuration of the Ethernet interface can be realized by the link aggregation and the spanning tree.

According to the spanning tree, the communication device
If there are multiple routes to the packet transfer destination device,
Normally, only one of the routes is kept alive, and when a failure occurs in that route, it is switched to another route.

Further, according to link aggregation,
By bundling a plurality of physical links into one logical link, the communication device can maintain communication even if one physical link in the logical links fails.

[0006]

In order to execute spanning tree or link aggregation, communication devices are required to perform complicated protocol processing. Therefore, the method using these has a problem that the switching time of the route is long. Further, the processing capacity of the communication device has been under pressure in order to execute complicated protocol processing.

An object of the present invention is to provide a communication device which does not require complicated protocol processing and has a redundant configuration with a short switching time.

[0008]

In order to achieve the above object, the Ethernet communication device of the present invention is an Ethernet communication device connected to two links, and the failure information indicates that the status of each link is normal. There is a link abnormality determining unit that determines whether there is an abnormality, a switching control unit that uses the determination result of the link abnormality determining unit to select a link for acquiring received data, When data is transmitted and received by a link, and the corresponding link is selected by the switching control means as a link for acquiring the received data, the data received from the link is taken out as the received data and the failure of the link is detected. Then, it has two transmitting / receiving means for notifying the failure information to the link abnormality determining means.

According to the present invention, the selection of valid links is changed upon the occurrence of a link abnormality.

In the Ethernet communication device of the present invention,
The two transmission / reception units may transmit the same data to the corresponding links regardless of whether or not the corresponding links are selected by the switching control unit as the links for acquiring the reception data.

According to the present invention, since the same data is transmitted to the two links, the effective link selection can be changed only by the receiving side device which has detected the link abnormality.

Further, there is further provided a duplication status setting means for notifying the switching control means and the transmission / reception means of either duplication or unification selected by the user, and the switching control means is provided from the duplication status setting means. When the duplexing is notified from the duplexing state setting means, the operation is stopped when the duplexing is notified, and when the duplexing is notified from the duplexing state setting means, the two transmitting / receiving means transmit the same data. Then, when one of the transmission / reception means selected as the link for acquiring the reception data receives the reception data and is notified of the unification, the two transmission / reception means respectively transmit different data. However, different reception data may be acquired for each link.

In the Ethernet communication apparatus of the present invention, the switching control means and the transmission / reception means select the operation according to the user setting information notified from the duplexing state setting means, so that the two links are duplexed or singled. You can switch whether to use as a link.

The Ethernet communication device of the present invention further comprises link abnormality threshold setting means for notifying the link abnormality determining means of the threshold value set by the user, and the link abnormality determining means uses the failure information for each of the links. The threshold value may be used when determining whether the state is normal or abnormal.

According to the present invention, the link abnormality determining means is
The link abnormality can be determined using the threshold set by the user notified from the link abnormality threshold setting means.

In the Ethernet communication device of the present invention,
It is preferable that the transmission / reception unit detect a disconnection of the link as the failure.

Further, it is preferable that the transmitting / receiving means detects a CRC error in decapsulation as the fault.

In the Ethernet communication device of the present invention,
The transmission / reception unit may store the data received from the link in the FIFO in synchronization with the line clock, read the data from the FIFO in synchronization with the internal clock, and obtain the reception data.

Further, it is preferable that the internal clock has a speed twice or more the speed of the line clock.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a communication device according to an embodiment of the present invention. Referring to FIG. 1, the communication device 1 includes a 0-system transmitting / receiving unit 10, a 1-system transmitting / receiving unit 30, a bus control unit 41, a link abnormality determination unit 51, and a switching control unit 5.
Have two. 0 system transmitter / receiver 10 and 1 system transmitter / receiver 30
Means that the link and the transmission / reception function of the communication device are duplicated.

The 0-system transmission / reception unit 10 includes a transmission physical interface 11, an encoding / inverse conversion unit 12, a frame encapsulation unit 13, a reception physical interface 14, and a link break detection unit 1.
5, a coding conversion unit 16, a frame decapsulation unit 17, and a timing adjustment unit 18. The transmission physical interface 11, the encoding deconversion unit 12, the frame encapsulation unit 13, the reception physical interface 14, the link disconnection detection unit 15, the encoding conversion unit 16, and the frame decapsulation unit 17 define by IEEE802.3. The functions of the existing PHY, PMD, PMA, and PCS are realized.

Similarly, the 1-system transmission / reception unit 30 includes a transmission physical interface 31, an encoding inverse conversion unit 32, a frame encapsulation unit 33, a reception physical interface 34, a link break detection unit 35, an encoding conversion unit 36, a frame conversion unit. It has an encapsulation unit 37 and a timing adjustment unit 38.

The frame encapsulation unit 13 encapsulates the data 114 from the timing adjustment unit 18 into an Ethernet frame and sends it to the encoding inverse conversion unit 12. The encapsulation processing includes preamble addition, CRC calculation, and FDC addition.

Similarly, the frame encapsulation unit 33 encapsulates the data 134 from the timing adjustment unit 38 into an Ethernet frame and sends it to the encoding / inverse conversion unit 32.

The encoding / inverse conversion unit 12 receives the Ethernet frame data 113 encapsulated in the frame encapsulation unit 13, converts it to 4B / 5B, and transmits it to the transmission physical interface 11.

Similarly, the encoding / inverse conversion unit 32 receives the Ethernet frame data 133 encapsulated by the frame encapsulation unit 33, converts it into 4B / 5B, and transmits it to the transmission physical interface 31.

The transmission physical interface 11 receives the data 112 that has been 4B / 5B converted by the encoding / inverse conversion unit 113 and transmits it to the Ethernet line 111.

Similarly, the transmission physical interface 31 is
Data 1 which has been 4B / 5B converted by the encoding inverse conversion unit 133
32 is received and transmitted to the Ethernet line 131.

The receiving physical interface 14 is the line 11
The data is received from 6 and transmitted to the link disconnection detecting unit 15.

Similarly, the receiving physical interface 34 is
The data is received from the line 136 and transmitted to the link disconnection detecting unit 35.

The link break detection unit 15 detects a link break by the data 117 received from the reception physical interface 14, and transmits the data to the coding converter 16. When the link break detection unit 15 detects a link break, the link break detection signal 151 outputs the link break detection signal 151.
Send to 1.

Similarly, the link break detection unit 35 detects the link break by the data 137 received from the reception physical interface 34, and transmits the data to the coding converter 36. Further, when the link disconnection detection unit 35 detects the link disconnection, it transmits a link disconnection detection signal 152 to the link abnormality determination unit 51.

The encoding conversion unit 16 includes a link disconnection detection unit 15
The data 118 from is converted to 5B / 4B and transmitted to the frame decapsulation unit 17.

Similarly, the encoding conversion unit 36 performs 5B / 4B conversion on the data 138 from the link disconnection detection unit 35 and transmits it to the frame decapsulation unit 37.

The frame decapsulation unit 17 decapsulates the Ethernet frame of the data 119, which has been 4B / 5B converted by the encoding conversion unit 16, and performs the timing adjustment unit 1.
Send to 8. The decapsulation process includes CRC error detection. The CRC error is the C
Result of RC operation and CRC added to frame
It is detected by comparing with the value. When the frame decapsulation units 17 and 37 detect the CRC error, the C
The RC error detection signal 153 is transmitted to the link abnormality determination unit 51.

Similarly, the frame decapsulation unit 37 is
Data 139 that has been 4B / 5B converted by the encoding conversion unit 36
The Ethernet frame is decapsulated and transmitted to the timing adjustment unit 38. Frame decapsulation unit 37
When detecting a CRC error, sends a CRC error detection signal 154 to the link abnormality determination unit 51.

The link abnormality determining section 51 has the link disconnection detection signals 151 and 152 and the CRC error detection signal 153.
From 154, disconnection of line 116, 136 or CR
The C error is acquired, and the link status signal 155 including the status of each link is transmitted to the switching control unit 52. The link status is a normal status or a link abnormal status due to a link disconnection or a CRC error.

The switching control unit 52 includes a link abnormality determination unit 51.
The link status signal 155 is received, and it is determined which system should be the active system from the status of each link and the active system information managed by itself. Then, the switching control unit 52
Sends a timing control signal to the timing adjustment unit of the system that should be the active system. The active system information is information including which system is currently the active system. The timing control signal is a signal for instructing execution of timing control, that is, a signal indicating an active system. When the 0 system is to be the active system, the timing control unit 52 transmits the timing control signal 156 to the timing adjustment unit 18. Further, when the first system is to be the active system, the timing control unit 52 transmits the timing control signal 157 to the timing adjustment unit 38.

The determination of which system should be the active system is
As a general rule, the system in which neither link disconnection nor CRC error has occurred is the active system. This is the link status signal 1
It can be judged only from 55. When a CRC error occurs in both systems, the switching control unit 52 maintains the current operating system as an example. The operational information is used for this determination.

The timing adjustment unit 18 adjusts the timing of the data 120 received from the frame decapsulation unit 17 only when receiving the timing control signal 156, and transmits it to the bus control unit 41. Each unit from the reception physical interface 14 to the frame decapsulation unit 17 is
In synchronization with the line clock 201, the bus control unit 41
Are synchronized with the internal clock 202. Timing adjustment is to transfer data between these clocks. The internal clock 202 is twice as fast as the line clock 201.

The timing adjusting section 18 does not transmit data to the bus controlling section 41 when the timing control signal 156 is not received.

Further, the timing adjusting section 18 always receives the data 115 from the bus controlling section 41, adjusts the timing to the line clock 201, and then the frame encapsulating section 13
Send to.

Similarly, the timing adjustment unit 38 receives the data 140 received from the frame decapsulation unit 37, adjusts the timing, and transmits the data 140 to the bus control unit 41 only when receiving the timing control signal 157. . From the reception physical interface 34 to the frame decapsulation unit 3
Each unit up to 7 is synchronized with the line clock 201.

The timing adjusting section 38 does not transmit data to the bus control section 41 when the timing control signal 157 is not received.

The timing adjusting unit 38 always receives the data 135 from the bus control unit 41, adjusts the timing to the line clock 201, and then the frame encapsulating unit 33.
Send to.

The bus control unit 41 includes the timing adjustment unit 1
The data 121 and 141 from 8 and 38 are received and output as the reception data 142. The data 121 from the timing adjustment unit 18 and the data 141 from the timing adjustment unit 38 are not received at the same time, but only one of them is received. The bus control unit 41 transmits one of the received data as reception data 142 to a switch unit (not shown).

Further, the bus control unit 41 uses the same data received from the switch unit as the 0-system timing adjustment unit 18
And the timing adjustment unit 38 of the first system. As a result, in the receiving unit of the opposite device, it is possible to immediately switch the operating system only by changing the selection of the system that captures the Ethernet frame.

FIG. 2 shows the timing adjusting section 1 of this embodiment.
8 is a block diagram showing a configuration of No. 8. Timing adjustment unit 3
8 has the same configuration. Referring to FIG. 2, the timing adjustment unit 18 includes a transmission data writing control unit 63 and a FIFO.
62, a transmission data read control unit 61, a reception data writing unit 6
4, a FIFO 65, and a reception data read control unit 66. The transmission data writing control unit 63, the FIFO 62 and the transmission data reading control unit 61 constitute the transmitting side, and the reception data writing unit 64, the FIFO 65 and the reception data reading control unit 66 constitute the receiving unit.

The transmission data read control unit 61 and the reception data write control unit 64 are supplied with the line clock 201, and the transmission data writing unit 63 and the reception data read unit 66 are supplied with the internal clock 202 and timing control. Signal 156 is provided.

The transmission data write control unit 63 operates in synchronization with the internal clock 202. The transmission data writing control unit 63 receives the data 115 from the bus control unit 41,
The data is written to the FIFO 62 by the internal clock 202.

The transmission data read control unit 61 operates in synchronization with the line clock 201. The transmission data read control unit 61 reads data from the FIFO 62 according to the line clock 201 and sends the data as data 114 to the frame encapsulation unit 13.

The reception data writing control unit 64 operates in synchronization with the line clock 201. The reception data writing control unit 64 uses the data 1 from the frame decapsulation unit 17.
20 is received, and its data is written in the FIFO 65 by the line clock 201.

The reception data read control unit 66 operates in synchronization with the internal clock 202. The reception data read control unit 66 receives the timing control signal 15 from the switching control unit 52.
While receiving 6
The data is read from the O62 and transmitted as the data 121 to the bus control unit 41.

An operation example of the communication device 1 of the present embodiment will be described.

FIG. 3 is a timing chart for explaining the transmission operation of the communication device 1 of this embodiment. As shown in FIG. 3, the bus control unit 41 includes a switch unit (not shown).
And receives the same data 115 and 135 to both the 0-system timing adjusting section 18 and the 1-system timing adjusting section 38. Since the internal clock 202 is twice as fast as the line clock 201, the data 14
3 has, on average, less than half the time slots with valid data. Here, as an example, time slots having valid data and time slots having no valid data are alternately present.

The data from the bus control unit 41 is adjusted in timing by the timing adjustment unit 18, encapsulated by the frame encapsulation unit 13, and encoded / inverted conversion unit 1
4B / 5B is converted by 2 and transmitted from the transmission physical interface 11 to the line 11.

FIG. 4 is a timing chart for explaining the receiving operation of the communication device 1 of this embodiment.

The data received by the reception physical interface 14 is judged by the link break detection unit 15 whether the link is broken or not, the coding conversion unit 16 performs 5B / 4B conversion, and the frame decapsulation unit 17 performs CRC. It is determined whether or not there is an abnormality, and it is transmitted to the timing adjustment unit 18. The 1-system transmitting / receiving unit 30 operates in the same manner.

The link abnormality determination unit 51 switches the state of each link based on the link disconnection detected by the link disconnection detection units 15 and 35 and the CRC error detected by the frame decapsulation units 17 and 37. 52 is notified. The switching control unit 52, which has been notified of the state of each link, determines which system should be the active system based on the current operating system and the state of each link, and notifies the timing adjusting units 18 and 38.

If the 0-system is the active system, the timing adjusting section 18 uses the data 1 from the frame decoupling section 17.
20 is adjusted in timing and transmitted to the bus control unit 41.
If the first system is the active system, the timing adjustment unit 38 adjusts the timing of the data 140 from the frame decoupling unit 37 and transmits the data 140 to the bus control unit 41. Bus control unit 4
1 is a timing adjustment unit 18 or a timing adjustment unit 3
The data from 8 is transmitted to the switch unit (not shown). FIG. 4 shows the case where the 0-system is the active system, and the 0-system data 120 is transmitted from the bus control unit 41 to the switch unit.

According to this embodiment, the communication device 1 transmits the same data to both the active system link and the standby system link in the transmission process, and is detected by the link disconnection detection units 15 and 35 in the reception process. Since the Ethernet link is switched in response to the link disconnection and the CRC error detected by the frame decapsulation units 17 and 37, the time from the occurrence of the failure to the link switching is short.

Further, according to the present embodiment, the communication device 1
Is a link abnormality determination unit 51 and a switching control unit 5 having simple functions.
Since the link switching operation can be performed by newly providing 2 and the timing adjusting unit 18, there is no need to implement complicated protocol processing.

Another embodiment of the present invention will be described.

FIG. 5 is a block diagram showing a configuration of a communication device according to another embodiment of the present invention. Referring to FIG.
The communication device 2 includes a transmission / reception unit 20, a transmission / reception unit 40, a bus control unit 41, a link abnormality determination unit 53, a switching control unit 54, a duplex state setting unit 71, and a link abnormality threshold setting unit 72. The bus control unit 41 of FIG. 5 is the same as that of FIG.

The transmission / reception unit 20 includes a transmission physical interface 11, an encoding / inverse conversion unit 12, and a frame encapsulation unit 1.
3, reception physical interface 14, link disconnection detection unit 1
5, a coding conversion unit 16, a frame decapsulation unit 17, and a timing adjustment unit 28. The transmission physical interface 11, the encoding deconversion unit 12, the frame encapsulation unit 13, the reception physical interface 14, the link disconnection detection unit 15, the encoding conversion unit 16, and the frame decapsulation unit 17 are the same as those in FIG.

Similarly, the transmission / reception unit 40 includes a transmission physical interface 31, an encoding inverse conversion unit 32, a frame encapsulation unit 33, a reception physical interface 34, a link break detection unit 35, an encoding conversion unit 36, and a frame decapsulation. Part 3
7 and a timing adjusting unit 48. The transmission physical interface 31, the encoding deconversion unit 32, the frame encapsulation unit 33, the reception physical interface 34, the link disconnection detection unit 35, the encoding conversion unit 36, and the frame decapsulation unit 37 are the same as those in FIG.

The duplex status setting unit 71 receives the duplex setting signal 171 from the user interface (not shown),
The information contained in the signal is held, and the switching control unit 62 and the timing adjusting units 28 and 48 are held according to the information.
Is instructed to duplex or single. The duplex setting signal 171 is a signal including information as to whether two links are used in duplex or used as separate links independent of each other.

The switching control unit 54 includes a duplex state setting unit 71.
Signal 172 including an instruction from the device, and operates according to the instruction. If the instruction from the duplexing state setting unit 71 is duplexing, the switching control unit 54 operates similarly to the switching control unit 51 in FIG. 1. If the instructions are unified, the switching control unit 5
4 does not work.

The link abnormality threshold setting unit 72 receives the threshold setting signal 173 from the user interface (not shown), holds the threshold information contained in the signal, and instructs the link abnormality determining unit 53 about the threshold. . The threshold may be, for example, a link disconnection duration for determining a link abnormality, a CRC error rate, or the like.

The link abnormality determining unit 53 uses the threshold value instructed by the link abnormality threshold value setting unit 72 when determining the link abnormality.

The timing adjusting units 28 and 48 receive the signal 172 including the instruction from the duplexing state setting unit 71, and operate according to the instruction.

If the instruction from the duplexing state setting unit 71 is duplexing, the timing adjusting units 28 and 48 operate in the same manner as the timing adjusting units 18 and 38 of FIG.

If the instruction is unified, the timing adjusting units 28 and 48 receive the data 120 received from the frame decapsulating units 17 and 37 regardless of the presence or absence of the timing control signals 156 and 157 from the switching control unit 54. , 140
Is adjusted and transmitted to the bus control unit 41. Therefore, as shown in FIG. 6, both data from the 0 system and the 1 system are transmitted to the switch unit (not shown) as the reception data 142 via the bus control unit 41. Further, as shown in FIG. 7, in the case of unification, the transmission data 143 from the switch unit (not shown) includes the data to the transmission / reception unit 20,
The data for the transmission / reception unit 40 are included. here,
The bus control unit 41 alternately receives data to the transmitting / receiving unit 20 and data to the transmitting / receiving unit 40 at different timings. Internal clock 202 is line clock 201
It's more than twice as fast, so that's possible. The timing adjustment unit 28 and the timing adjustment unit 48 send different data to the bus control unit 4 when the instruction is single.
Get from 1.

According to this embodiment, the communication device 2 holds the setting information as to whether or not the duplexing is set by the duplexing state setting section 71, and the switching control section 54 and the timing adjusting section 28,
Since 48 selects an operation according to the setting information, when high reliability is required, two links are used as a duplicated link, and when it is required to transfer a large amount of traffic at low cost. It is possible to flexibly meet the requirements of the user by using the two links as a single link.

In the communication device 2, the link abnormality threshold value setting unit 72 holds the threshold value so that it can be changed, and the link abnormality determination unit 53 uses the threshold value to determine the link abnormality. By using an appropriate threshold value, it is possible to flexibly meet user requirements for channel quality.

[0077]

According to the present invention, since the selection of valid links is changed in response to the occurrence of a link abnormality, complicated protocol processing is not required, and valid links are appropriate from the occurrence of a failure. It takes a short time to be selected.

Further, since the same data is transmitted to the two links, the selection of the valid link can be changed only by the receiving side device which has detected the link abnormality, and the valid link is properly selected from the occurrence of the failure. Time is short.

Further, the switching control means and the transmission / reception means select the operation according to the user setting information notified from the duplexing state setting means, thereby switching between two links to be duplexed or two links to be singled. Therefore, when high reliability is required, two links are used as duplicated links, and when it is required to transfer a large amount of traffic at low cost, two links are used as a single link. By using it, it is possible to flexibly meet the requirements of the user.

Further, since the link abnormality determining means determines the link abnormality using the threshold value set by the user notified from the link abnormality threshold setting means, by using an appropriate threshold value in accordance with the user request for the line quality, It is possible to flexibly meet user requirements for line quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a timing adjusting unit according to the embodiment of the present invention.

FIG. 3 is a timing chart for explaining a transmission operation of the communication device according to the embodiment of the present invention.

FIG. 4 is a timing chart for explaining a reception operation of the communication device according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a communication device according to another embodiment of the present invention.

FIG. 6 is a timing chart for explaining a reception operation of the communication device according to another embodiment of the present invention.

FIG. 7 is a timing chart for explaining a transmission operation of the communication device according to another embodiment of the present invention.

[Explanation of symbols]

1, 2 Communication Device 10 0 Transmitting / Receiving Unit 11 Transmission Physical Interface 12 Encoding Inverse Conversion Unit 13 Frame Encapsulation Unit 14 Reception Physical Interface 15 Link Loss Detection Unit 16 Encoding Conversion Unit 17 Frame Decapsulation Units 18 and 28 Timing Adjustment Unit 30 1-system transmitting / receiving unit 31 Transmission physical interface 32 Encoding inverse conversion unit 33 Frame encapsulation unit 34 Reception physical interface 35 Link break detection unit 36 Encoding conversion unit 37 Frame decapsulation units 38, 48 Timing adjustment unit 41 Bus control Units 51, 53 Link abnormality determination units 52, 54 Switching control unit 61 Transmission data read control units 62, 65 FIFO 63 Transmission data writing control unit 64 Reception data writing unit 66 Reception data reading control unit 71 Duplex state setting unit 72 Link error threshold settings 111, 116, 131, 1 Six lines 112～115,117～121,132～135,1
37 to 141, 211 to 214 Data 142 Received data 143 Transmitted data 151, 152 Link disconnection detection signal 153, 154 CRC error detection signal 155 Link status signal 156, 157 Timing control signal 171 Duplication setting signal 172, 174 signal 173 Threshold setting signal 201 Line clock 202 Internal clock

Claims (8)

[Claims] 1. An Ethernet communication device connected to two links, comprising: a link abnormality determining means for determining whether the status of each link is normal or abnormal from failure information; and a link abnormality determining means. A switching control unit that selects a link for acquiring received data using the determination result, and is connected to each of the links to transmit and receive data through the link, and the corresponding link acquires the received data. When the link is selected by the switching control means, the data received from the link is taken out as reception data, and when the failure of the link is detected, the failure information is notified to the link abnormality determination means. Ethernet communication device. 2. The two transmitting / receiving means transmit the same data to the corresponding link regardless of whether the corresponding link is selected by the switching control means as a link for acquiring received data. Claim 1
The described Ethernet communication device. 3. A duplication status setting means for notifying the switching control means and the transmission / reception means of either duplication or unification selected by a user, wherein the switching control means is provided from the duplication status setting means. When the duplexing is notified from the duplexing state setting means, the transmission / reception means operates to stop the operation when the duplexing is notified, and the transmission / reception means transmits the same data when the duplexing is notified from the duplexing state setting means. Then, when one of the transmission / reception means selected as the link for acquiring the reception data receives the reception data and is notified of the unification, the two transmission / reception means respectively transmit different data. The Ethernet communication device according to claim 1, wherein different received data is obtained for each link. 4. A link abnormality threshold value setting means for notifying the link abnormality determination means of a threshold value set by a user, wherein the link abnormality determination means has a normal state of each link from the failure information. The Ethernet communication device according to any one of claims 1 to 3, wherein the threshold value is used when determining whether it is abnormal. 5. The Ethernet communication device according to claim 1, wherein the transmission / reception unit detects a broken link as the failure. 6. The transmission / reception unit detects a CRC error in decapsulation as the fault.
3. The Ethernet communication device according to any one of 3 above. 7. The transmitting / receiving means stores the data received from the link in a FIFO in synchronization with a line clock, reads the data from the FIFO in synchronization with an internal clock, and acquires the data as the received data. Item 1
4. The Ethernet communication device according to any one of 3 to 3. 8. The Ethernet communication device according to claim 7, wherein the internal clock is at least twice as fast as the line clock.